The cache fsynced every payload and manifest -- two per entry, ~18 ms, and a
push publishes one entry per question (~22,000 on a WordPress plugin). A
read already rejects any entry whose manifest receipt, payload size or
payload SHA-256 does not check, so a torn write is a miss, never a wrong
answer; the fsyncs bought nothing the verification does not.
The broader problem: three quadratic walls in this replay were found one
per two-hour run, because all were Python bookkeeping between engine calls
and the only record was the engine log. `OUSAST_SAMPLE_PROFILE=<path>`
starts an in-process sampler that rewrites the hottest stacks every 30 s,
so a run killed at its deadline still names where its time went. The host
cannot ptrace the container, hence in-process. The replay harness turns it
on per case.
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
Claude-Session: https://claude.ai/code/session_01EmM1j46qgKMh3zqD1QMwEo
